1. Field of the Invention
The present invention relates to a rotating body that is suitable for use in, for example, a rotor of a steam turbine.
Priority is claimed on Japanese Patent Application No. 2009-164780, filed Jul. 13, 2009, the content of which is incorporated herein by reference.
2. Description of Related Art
As is well known, a steam turbine that converts thermal energy of steam into kinetic energy by rotating a rotor with steam is widely employed in the driving of a compressor in power generation and chemical plants.
As a rotor that is used in this kind of steam turbine, there is one that is equipped with a rotor disk that is provided on the outer circumference of a rotor shaft, and a plurality of moving blades that are consecutively provided on the outer circumference of this rotor disk. In this kind of rotating body, it is necessary to firmly fix the rotor disk and the moving blades so as to be able to sufficiently tolerate the centrifugal force, vibration stress, and bending stress that arise during high-speed rotation.
For example, in Patent Document 1 given below, a rotating body is disclosed that is provided with a rotor disk that has a moving blade fitting groove that is annularly provided along the outer circumference and a moving blade lead-in hole that is provided in the outer circumference and is in communication with the moving blade fitting groove, moving blades that each have a blade root that is fitted in the moving blade fitting groove, a disk pin that passes through the blade root of the moving blade that is placed last at the moving blade lead-in hole and the rotor disk in the axial direction, and a blade pin that is provided within the moving blade that is placed last, interlocks with the disk pin and projects to both sides in the circumferential direction. That is, in this rotating body, the moving blade that is placed last and other moving blades are fixed by causing engagement of a hollow portion that is formed in both adjacent moving blades of the moving blade that is placed last and the blade pin.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2004-108290
In order to achieve higher output and higher speed rotation of the steam turbine, it is necessary to fix the moving blades to the rotor disk with additional firmness so that the moving blades do not detach as a result of high-speed rotation. However, since in the prior art the moving blades are simply attached by causing engagement of the hollow portions that are formed in the moving blades and the blade pin of the moving blade placed last, even if the strength of the blade pin is increased or the formation dimensions are optimized, the fixing property of the moving blades is insufficient.
As a structure that is capable of firmly fixing the moving blades, it is possible to mention the following structure that is disclosed as prior art in the aforementioned Patent Document 1. That is, this structure is provided with a rotor disk that has a moving blade fitting groove and a moving blade lead-in hole, moving blades that each have a blade root, two special moving blades that are mutually adjacent and block the moving blade lead-in hole and in which a portion of each respective blade root fits in the moving blade fitting groove, and a tensioning key that is inserted between the moving blades. By inserting the tensioning key between the moving blades, the positions of the two special moving blades are adjusted, and by passing a stop pin through the blade roots of the special moving blades and the rotor disk, movement in the circumferential direction of the moving blades and the special moving blades is restrained.
In this kind of structure, since a portion of the blade roots of the special moving blades is fitted in the moving blade fitting groove, it is possible to firmly fix the moving blades and the special moving blades.
However, in the aforementioned structure, there is the problem in which the fixing property of the tensioning key must be increased so that the tensioning key does not detach as a result of high-speed rotation.
The present invention was achieved in view of the aforementioned circumstances, and has as its object to provide a rotating body in which the tensioning key and the moving blades and the special moving blades are firmly attached.